Experimental study of a low-order wavefront sensor for high-contrast coronagraphic imagers
Abstract
For the technology development of the mission EXCEDE (EXoplanetary Circumstellar Environments and Disk Explorer) - a 0.7 m telescope equipped with a Phase-Induced Amplitude Apodization Coronagraph (PIAA-C) and a 2000-element MEMS deformable mirror, capable of raw contrasts of 1e-6 at 1.2 λ/D and 1e-7 above 2 λ/D - we developed a test bench simulating it’s key components. To achieve this level of contrast, one of the main goals is to remove low-order aberrations, using a Low-Order WaveFront Sensor (LOWFS). An experiment simulating the starlight suppression system is currently developed at NASA Ames Research Center, and includes a LOWFS controlling tip/tilt modes in real time at 1 kHz. The LOWFS allowed us to reduce the tip/tilt disturbances to 1e-3 λ/D rms, letting us achieve a contrast of 4e-7 between 1.2 and 2 λ/D. Also by studying accurately this system, and by comparing it to simulations, we are able to deduce its performances on different coronagraphs - different sizes of telescopes, inner working angles, contrasts, etc. - and therefore study its contribution beyond EXCEDE.
- Publication:
-
American Astronomical Society Meeting Abstracts #223
- Pub Date:
- January 2014
- Bibcode:
- 2014AAS...22310509L